Evidence is compelling for a positive correlation between urbanisation and increment of allergic sensitisation and diseases. The reason for this association is not clear to date. Some data point to a pro-allergic effect of anthropogenic factors on susceptible individuals. Data analysing the impact of environmental - natural and anthropogenic - factors on the allergenicity of allergen carriers such as pollen grains are scarce, and if applicable only taken from in vitro experimental designs. This study will analyse one of the most common allergy inducers in northern Europe - the birch pollen. Under natural exposure conditions, birch pollen will be analysed with respect to their allergenicity. Within an interdisciplinary research team this study will evaluate the effect of natural (e.g. soil, climate, genetic background) and anthropogenic (e.g. traffic pollutants) factors on birch pollen in a holistic approach including analysis of allergen bioavailability, release of pollen associated lipid mediators from birch pollen grains, in vitro immunostimulatory activity and in vivo allergenic potential. These data collected in the time course of three years will significantly add to our understanding how urbanisation and climate change influence the allergenicity of birch pollen and will help us in the future to set up primary prevention studies.
Water is an intrinsic component of ecosystems acting as a key agent of lateral transport for particulate and dissolved nutrients, forcing energy transfers, triggering erosion, and driving biodiversity patterns. Given the drastic impact of land use and climate change on any of these components and the vulnerability of Ecuadorian ecosystems with regard to this global change, indicators are required that not merely describe the structural condition of ecosystems, but rather capture the functional relations and processes. This project aims at investigating a set of such functional indicators from the fields of hydrology and biogeochemistry. In particular we will investigate (1) flow regime and timing, (2) nutrient cycling and flux rates, and (3) sediment fluxes as likely indicators. For assessing flow regime and timing we will concentrate on studying stable water isotopes to estimate mean transit time distributions that are likely to be impacted by changes in rainfall patterns and land use. Hysteresis loops of nitrate concentrations and calculated flux rates will be used as functional indicators for nutrient fluxes, most likely to be altered by changes in temperature as well as by land use and management. Finally, sediment fluxes will be measured to indicate surface runoff contribution to total discharge, mainly influenced by intensity of rainfall as well as land use. Monitoring of (1) will be based on intensive sampling campaigns of stable water isotopes in stream water and precipitation, while for (2) and (3) we plan to install automatic, high temporal-resolution field analytical instruments. Based on the data obtained by this intensive, bust cost effective monitoring, we will develop the functional indicators. This also provides a solid database for process-based model development. Models that are able to simulate these indicators are needed to enable projections into the future and to investigate the resilience of Ecuadorian landscape to global change. For the intended model set up we will couple the Catchment Modeling Framework, the biogeochemical LandscapeDNDC model and semi-empirical models for aquatic diversity. Global change scenarios will then be analyzed to capture the likely reaction of functional indicators. Finally, we will contribute to the written guidelines for developing a comprehensive monitoring program for biodiversity and ecosystem functions. Right from the beginning we will cooperate with four SENESCYT companion projects and three local non-university partners to ensure that the developed monitoring program will be appreciated by locals and stakeholders. Monitoring and modelling will focus on all three research areas in the Páramo (Cajas National Park), the dry forest (Reserva Laipuna) and the tropical montane cloud forest (Reserva Biologica San Francisco).
Sandy soils of the arid/semiarid dune fields of the Palestinian Gaza Strip and the Israeli western Negev are extensively covered by biological soil crusts (BSC), which stabilize the surface and prevent desertification. Political discussions in Israel suggest transferring a large part of this sand belt to the Gaza Strip within a final peace accord. Inappropriate land uses may lead to destruction of the BSC and initiate desertification, as already occurring in parts of the Gaza Strip. In this interdisciplinary project the influence of environmental factors on the vitality, stability and the recovery potential of the BSC will be investigated in order to evaluate the carrying capacity of this fragile landscape, in relation to rainfall, soil and relief conditions. A transect stretching from the Mediterranean coast in the Palestinian Gaza Strip (370 mm rainfall) to 65 km southwards in Israel ( Nizzana , less than 100 mm rainfall) has been selected. The interactions of molecular biological, physiological, physical and soil chemical processes, expressed in specific characteristics of the BSC and the underlying soil, will be assessed from the molecular to the landscape scale.
In the last decades agricultural policy has gained increasingly in complexity. Nowadays it influences the food and agricultural sector from the global market down to the farm level. Widespread research questions, like the impact of the WTO negotiations on the farm structure, most often require comprehensive modeling frameworks. Thus, different types of models are utilized according to their comparative advantages and combined in a strategically useful way to more accurately represent micro and macro aspects of the food and agricultural sector. Consequently, in recent years we have seen an increase in the development and application of model linkages. Given this background, the overall objective of this subproject is a systematic sensitivity analysis of model linkages that gradually involves more and more characteristics of the linkage and the corresponding transfer of results between models. In addition, the project aims to answer the following specific question: How does structural change at the farm level influence aggregate supply and technical progress? Under which conditions is it possible to derive macro-relationships from micro-relationships? How does the aggregation level influence the model results and how can possible problems be overcome? This procedure is used to quantify the effects and to derive conditions for optimal interaction of the connected models. The analysis is based on the general equilibrium model GTAP (Global Trade Analysis Project) and the farm group model FARMIS (Farm Modelling Information System) which are employed in conjunction to analyze the effects of WTO negotiations on the farm level.
Dissolved organic matter (DOM) is one major source of subsoil organic matter (OM). P5 aims at quantifying the impact of DOM input, transport, and transformation to the OC storage in the subsoil environment. The central hypotheses of this proposal are that in matric soil the increasing 14C age of organic carbon (OC) with soil depth is due to a cascade effect, thus, leading to old OC in young subsoil, whereas within preferential flowpaths sorptive stabilization is weak, and young and bioa-vailable DOM is translocated to the subsoil at high quantities. These hypotheses will be tested by a combination of DOC flux measurements with the comparative analysis of the composition and the turnover of DOM and mineral-associated OM. The work programme utilizes a DOM monitoring at the Grinderwald subsoil observatory, supplemented by defined experiments under field and labora-tory conditions, and laboratory DOM leaching experiments on soils of regional variability. A central aspect of the experiments is the link of a 13C-leaf litter labelling experiment to the 14C age of DOM and OM. With that P5 contributes to the grand goal of the research unit and addresses the general hypotheses that subsoil OM largely consists of displaced and old OM from overlying horizons, the sorption capacity of DOM and the pool size of mineral-associated OM are controlled by interaction with minerals, and that preferential flowpaths represent 'hot spots' of high substrate availability.
Soil microorganisms can mobilize and immobilize phosphorus (P), and therefore strongly affect the availability of P to plants. In this project we hypothesize that the ratio of labile P to microbial P increases during the transition from acquiring to recycling ecosystems. Microbial and plant P uptake will be studied with 33P that will be quantified in microbial and plant biomass as well as in lipids. To what extent microorganisms immobilize and mobilize P during decomposition of soil organic matter will be explored with a 14C/33P labeled monoester. Seasonal dynamics of actual and potential P mineralization (33P dilution and phosphatase activity), and microbial P immobilization will be studied with soils of the transition from acquiring to recycling ecosystems. The contribution of litter-derived P will be explored in a litter exclusion experiment in the field. Spatial patterns of microbial and plant P mineralization in the rhizosphere will be explored by analyses of areas of high acid and alkaline (=microbial-derived) phosphatase activity by soil zymography, and their relations with areas of high rhizodeposition (14C imaging). In conclusion, we will analyse mechanisms of actual and potential microbial P mineralization and immobilization, localization, and consequences for P uptake by plants.
Almond in California represents an agroecosystem pollinated solely by a single species, the European honey bee, a species that is becoming increasingly difficult and expensive to manage due to substantial, unpredictable mortality. Therefore, sustainable and high output production require a more integrated approach that diversifies sources of pollination. For this purpose, detailed data of our understanding how diversity can stabilize pollination are required. The project will identify alternative wild pollinator species and collect high quality data contributing to our understanding of how diversity (pollen and insects) can bolster honey bee pollination during stable and unstable climatic conditions. The research will be carried out on almond orchards in Northern California known to be either pollinator species rich (up to 30 species) or depauperate (honey bees only). The replicated extremes in pollinator diversity represent a unique opportunity to study the effects of diversity on pollination in real agroecosystems combined with laboratory and glasshouse experiments. The overall goal is to provide basic research that is essential for our general understanding of how insect diversity can affect high-quality pollination under land use and climate change.
Electrical conductivity is a key parameter in models of magnetic field generation in planetary interiors through magneto-hydrodynamic convection. Measurements of this key material parameter of liquid metals is not possible to date by experiments at relevant conditions, and dynamo models rely on extrapolations from low pressure/temperature experiments, or more recently on ab-initio calculations combining molecular dynamics and linear response calculations, using the Kubo-Greenwood formulation of transport coefficients. Such calculations have been performed for Fe, Fe-alloys, H, He and H-He mixtures to cover the interior of terrestrial and giant gas planets. These simulations are computationally expensive, and an efficient accurate scheme to determine electrical conductivities is desirable. Here we propose a model that can, at much lower computational costs, provide this information. It is based on Ziman theory of electrical conductivity that uses information on the liquid structure, combined with an internally consistent model of potentials for the electron-electron, electron-atom, and atom-atom interactions. In the proposal we formulate the theory and expand it to multi-component systems. We point out that fitting the liquid structure factor is the critical component in the process, and devise strategies on how this can be done efficiently. Fitting the structure factor in a thermodynamically consistent way and having a transferable electron-atom potential we can then relatively cheaply predict the electrical conductivity for a wide range of conditions. Only limited molecular dynamics simulations to obtain the structure factors are required.In the proposed project we will test and advance this model for liquid aluminum, a free-electron like metal, that we have studied with the Kubo-Greenwood method previously. We will then be able to predict the conductivities of Fe, Fe-light elements and H, He, as well as the H-He system that are relevant to the planetary interiors of terrestrial and giant gas planets, respectively.
In this project we experimentally explore the transport of engineered inorganic nanoparticles (EINP) through soils. This is done for original EINPs and some pre-aged form. Transport of NPs in soil is expected to be different from that of reactive solutes, in that hydrodynamic drag, inertial and shear forces as well as the affinity to water-gas interfaces are expected to be more relevant. Hence, the mobility of EINPs in soil is highly sensitive to the morphology of the porous structure and the dynamics of water saturation.This project provides the pore network structure for natural soils using X-ray micro-tomography to allow for an up-scaling of pore-scale interactions explored by project partners to the scale of soil horizons. The pore structure is represented by a network model suitable for pore scale simulations including the dynamics of water-gas interfaces.Pore network simulations will be compared to column experiments for conservative tracers as well as for unaltered and pre-aged EINPs (obtained from INTERFACE). This includes steady state flow scenarios for saturated (ponding) and unsaturated conditions as well as for transient flow to explore the impact of moving water-gas interfaces. The final goal is to arrive at a consistent interpretation of experimental findings and numerical simulations to develop a module for modelling EINP transfer through soil as a function of particle properties, soil structural characteristics and external forcing in terms of flux boundary conditions.
The vegetation of East and South African savannahs has been shaped by the complex interaction of geo-biophysical processes and human impact. For both regions a controversial discussion is pertinent, as to whether massive degradation threatens the sustainability of livelihoods in these regions. Rangeland vegetation is mainly affected by environmental conditions (soil and climate) and by livestock management. Extent and interaction of these drivers are not well understood but have profound impacts on the resilience and vulnerability of these systems to be shifted toward unfavourable degraded or bush encroached states. The project aims to analyse and model rangeland vegetation in response to range management including livestock, soil quality and climatic conditions and to assess the impacts of changes in these conditions on the resilience and vulnerability of rangeland systems. Field measurements, remote sensing of vegetation patterns and dynamics and simulation modelling will be used to understand the dynamics of rangeland vegetation. We will use the 'fast' or 'state' variables potential of pastures to produce palatable biomass, the variability of this production, and the system's potential to recover from disturbance impact as indicators of resilience. 'slow' variables that control (or drive) the 'fast' variables such as management, climate and soil variables are recorded in cooperation with other subprojects as with A1 for soil variables. Results of the project will show which management activities are most favourable for individual regions to sustain plant production in the long term.
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